Excavatiira-machine



UNITED sTATEs PATENT oEFIoE.

NATHAN SAUNDERS AND F. T. SHERMAN, 0F CHICAGO, ILLINOIS.

EXCAVATINGMACHINE.

Specification of Letters Patent No. 20,511, dated J une 8, 1858.

To all whom it may concern:

Be it known that we, NATHAN SAUNDERS and F. T. SHERMAN, of Chicago, in the county of Cook and State of Illinois, have invented an Improvement in Excavators, and that the following is a full, clear, and exact description of the principle or character which distinguishes it from all other things before known and of the usual manner of making, modifying, and using the same, reference being had to the accompanying drawings, of which- Figure l is a perspective view of the excavator. Fig. 2, is a detached view of the slide rest. Fig. 3, is a perspective view of the extension fulcrum piece hereinafter described.

Our invention consists in certain improvements in excavators hereinafter described.

The excavator is similar in principle to those in common use and differs from them in construction and operation only in the slide rest A for sustaining the dipper shaft B and the movable fulcrum piece E near the extremity of the crane. The object of the movable fulcrum piece is to extend the dipper shaft after it has been raised to a considerable distance and thus carry the contents of the dipper or bucket farther than can be done by a stationary fulcrum. Upon the carriage E are two pulleys T, T over which the rope f runs which raises the dipper; this rope being wound up on windlass N. On one side of pulley T is fixed a pinion X which takes into a vibrating rack F. This rack is thrown into and out of gear with the pinion by the pin or projection a on the end of the lifting bar B which is operated by the handle B through the medium of the connecting rod m and lever n. When the free end of the rack is raised it is brought into gear with the pinion and the rotation of the pulley by t-he rope f turns the pinion thereby causing it to travel out along the rack toward the end of the crane and at the same time the dipper is moved alongby means about to be describedso as to keep the fulcrum a as near as practicable in the line of suspension of the dipper. When the extreme point of extension has been attained and the bucket emptied of its contents in the usual way the pinion X is thrown out of gear with t-he rack F and as the dipper shaft is withdrawn and lowered the carriage or fulcrum piece slides back on its ways to its original position. This extension of the fulcrum enables me to carry the contents of the dipper farther from the point of excavation than can be done by any crane having a fixed fulcrum.

The construction and operation of the slide rest are as follows. The dipper shaft C consists of two parallel beams and racks g, g, attached to each beameach having sutHcient space between them to admit the slide rest and also the rope f. These racks gear with the pinions S, S fixed to the shaft g driven by the pulley R and rope e by means of pulley P and crank z' and thus it will be seen that the attendant who attends to the shifting of arm B can turn the crank z' and extend or withdraw the dipper shaft. Between the pinions S, S, is the rotating slide rest A turning on the shaft g. This rest is bifurcated at the upper part as shown in Fig. 2 and each branch X2 is fitted at top so as to slide freely on the ways or guides b b as shown in Fig. 2. The mode at present in use for sustaining and guiding this part of the dipper shaft is to run it upon a friction roller, but the rotating sliding rest gives greater steadiness and strength.

We claim- The extension fulcrum piece in combination with the dipper shaft in the manner set forth, so that when the dipper shaft arrives at the point necessary for shifting the fulcrum the fulcrum piece may be thrown into gear and be carried to the extremity of the crane for the purposes set forth.

NATHAN SAUNDERS. F. T. SHERMAN.

Witnesses:

H. W. BAY, CHAs. L. WEBB. 

